A manufacturer of products that incorporates glass, such as a window manufacturer, receives orders for products which require different sizes of glass lites. The orders for the glass are separated and grouped into scheduled production batches. For each production batch, the glass lites are further grouped and arranged to be cut from large stock glass sheets to achieve the highest yield. The process of grouping and arranging glass lites to be cut from stock glass sheets to achieve the highest yield is called glass optimization.
Glass optimization is usually performed by a computer executing a computer program one hour to one day prior to use at the cutting station. The output from the glass optimization process is a control program that is sent to a computer-controlled cutting table. The glass optimization software outputs a computer program that optimizes one or more production batches containing patterns of lites arranged on stock glass sheets. The cutting table automatically scores the glass according to each pattern. Each production batch normally contains one or more glass layout patterns that provide a lower yield than desirable.
These Low Yield Patterns or Low Yield Sheets significantly reduce the yield of entire production batches resulting in higher manufacturing costs due to wasted glass. Waste is particularly expensive when manufacturing windows from increasingly popular specialty glasses such as Low-E or self-cleaning materials.
Today, there are several existing methodologies used to increase glass yields. Unfortunately, each method presents one or more problems to manufacturing operations. The methods and their resulting problems are described below.                a) Standard dimensioned lites called filler lites can be introduced to scheduled production batches to fill-in unused space on the stock glass sheets. The glass optimization software determines where filler lites can be inserted when creating the initial programmed patterns. Because fillers are inserted prior to the actual manufacturing process, the number and type of filler lites rarely meet actual production demand. Too few filler lites starve production lines while too many fillers create storage and quality problems.        b) Adding different sizes of large stock sheets also increase yield. This allows the glass optimization software to pick the size of stock sheets that produce the best yield. Although this method enhances yield, it also increases inventory space and costs while decreasing throughput (more glass sizes to shuttle in and out).        c) Certain cutting tables allow the lites from Low Yield Sheets to be added to manually entered or selected lites and re-optimized to increase yields. Although these features provide excellent flexibility and increase yield, they also cause the cutting table to remain idle during the manual entry process. This greatly reduced production throughput and efficiency.        